+ OpenSSL provides built-in support for two threading models: pthreads (found on
+ most UNIX/Linux systems), and Windows threads. No other threading models are
+ supported. If your platform does not provide pthreads or Windows threads then
+ you should Configure with the "no-threads" option.
+
+ Note on shared libraries
+ ------------------------
+
+ Shared libraries have certain caveats. Binary backward compatibility
+ can't be guaranteed before OpenSSL version 1.0. The only reason to
+ use them would be to conserve memory on systems where several programs
+ are using OpenSSL.
+
+ For some systems, the OpenSSL Configure script knows what is needed to
+ build shared libraries for libcrypto and libssl. On these systems,
+ the shared libraries are currently not created by default, but giving
+ the option "shared" will get them created. This method supports Makefile
+ targets for shared library creation, like linux-shared. Those targets
+ can currently be used on their own just as well, but this is expected
+ to change in future versions of OpenSSL.
+
+ Note on random number generation
+ --------------------------------
+
+ Availability of cryptographically secure random numbers is required for
+ secret key generation. OpenSSL provides several options to seed the
+ internal PRNG. If not properly seeded, the internal PRNG will refuse
+ to deliver random bytes and a "PRNG not seeded error" will occur.
+ On systems without /dev/urandom (or similar) device, it may be necessary
+ to install additional support software to obtain random seed.
+ Please check out the manual pages for RAND_add(), RAND_bytes(), RAND_egd(),
+ and the FAQ for more information.
+
+ Note on support for multiple builds
+ -----------------------------------
+
+ OpenSSL is usually built in its source tree. Unfortunately, this doesn't
+ support building for multiple platforms from the same source tree very well.
+ It is however possible to build in a separate tree through the use of lots
+ of symbolic links, which should be prepared like this:
+
+ mkdir -p objtree/"`uname -s`-`uname -r`-`uname -m`"
+ cd objtree/"`uname -s`-`uname -r`-`uname -m`"
+ (cd $OPENSSL_SOURCE; find . -type f) | while read F; do
+ mkdir -p `dirname $F`
+ rm -f $F; ln -s $OPENSSL_SOURCE/$F $F
+ echo $F '->' $OPENSSL_SOURCE/$F
+ done
+ make -f Makefile.in clean
+
+ OPENSSL_SOURCE is an environment variable that contains the absolute (this
+ is important!) path to the OpenSSL source tree.
+
+ Also, operations like 'make update' should still be made in the source tree.